UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.12.1, when ujson.dump() writes to a file-like object and the write operation raises an exception, the serialized JSON string object is not decremented, leaking memory. Each failed write operation leaks the full size of the serialized payload. This vulnerability is fixed in 5.12.1.
References
| Link | Resource |
|---|---|
| https://github.com/ultrajson/ultrajson/commit/82af1d0ac01d09aa40c887b460d44b9d9f4bccd9 | Patch |
| https://github.com/ultrajson/ultrajson/releases/tag/5.12.1 | Product Release Notes |
| https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg | Exploit Mitigation Patch Vendor Advisory |
| https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg | Exploit Mitigation Patch Vendor Advisory |
Configurations
History
02 Jun 2026, 18:00
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.5 |
| References | () https://github.com/ultrajson/ultrajson/commit/82af1d0ac01d09aa40c887b460d44b9d9f4bccd9 - Patch | |
| References | () https://github.com/ultrajson/ultrajson/releases/tag/5.12.1 - Product, Release Notes | |
| References | () https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg - Exploit, Mitigation, Patch, Vendor Advisory | |
| First Time |
Ultrajson Project ultrajson
Ultrajson Project |
|
| CPE | cpe:2.3:a:ultrajson_project:ultrajson:*:*:*:*:*:python:*:* |
30 May 2026, 02:16
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg - |
27 May 2026, 21:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-27 21:16
Updated : 2026-06-02 18:00
NVD link : CVE-2026-44660
Mitre link : CVE-2026-44660
CVE.ORG link : CVE-2026-44660
JSON object : View
Products Affected
ultrajson_project
- ultrajson
CWE
CWE-401
Missing Release of Memory after Effective Lifetime
